USAP-DC

{"dp_type": "Project", "free_text": "apatite"}

[{"awards": "1917176 Siddoway, Christine; 1916982 Teyssier, Christian; 1917009 Thomson, Stuart", "bounds_geometry": "POLYGON((-160.16 -67.15,-154.572 -67.15,-148.984 -67.15,-143.39600000000002 -67.15,-137.808 -67.15,-132.22 -67.15,-126.632 -67.15,-121.04400000000001 -67.15,-115.456 -67.15,-109.868 -67.15,-104.28 -67.15,-104.28 -68.165,-104.28 -69.18,-104.28 -70.19500000000001,-104.28 -71.21000000000001,-104.28 -72.225,-104.28 -73.24,-104.28 -74.255,-104.28 -75.27,-104.28 -76.285,-104.28 -77.3,-109.868 -77.3,-115.456 -77.3,-121.044 -77.3,-126.632 -77.3,-132.22 -77.3,-137.808 -77.3,-143.396 -77.3,-148.98399999999998 -77.3,-154.572 -77.3,-160.16 -77.3,-160.16 -76.285,-160.16 -75.27,-160.16 -74.255,-160.16 -73.24,-160.16 -72.225,-160.16 -71.21000000000001,-160.16 -70.19500000000001,-160.16 -69.18,-160.16 -68.165,-160.16 -67.15))", "dataset_titles": "Apatite fission track thermochronology data for detrital minerals, offshore clasts, and bedrock; U-Pb detrital zircon geochronological data, obtained by LA-ICP-MS", "datasets": [{"dataset_uid": "200332", "doi": "", "keywords": null, "people": null, "repository": "in progress", "science_program": null, "title": "U-Pb detrital zircon geochronological data, obtained by LA-ICP-MS", "url": ""}, {"dataset_uid": "200333", "doi": "", "keywords": null, "people": null, "repository": "in progress", "science_program": null, "title": "Apatite fission track thermochronology data for detrital minerals, offshore clasts, and bedrock", "url": ""}], "date_created": "Wed, 19 Oct 2022 00:00:00 GMT", "description": "Sediment records off the coast of Marie Byrd Land (MBL), Antarctica suggest frequent and dramatic changes in the size of the West Antarctic Ice Sheet (WAIS) over short (tens of thousands of years) and long (millions of years) time frames in the past. WAIS currently overrides much of MBL and covers the rugged and scoured bedrock landscape. The ice sheet carved narrow linear troughs that reach depths of two to three thousand meters below sea level as outlet glaciers flowed from the interior of the continent to the oceans. As a result, large volumes of fragmented continental bedrock were carried out to the seabed. The glaciers cut downward into a region of crystalline rocks (i.e. granite) that display a significant temperature change as a function of rock depth. The strong geothermal gradient in the bedrock is favorable for determining when the bedrock became exhumed, or \"uncovered\" by action of the overriding icesheet or other processes. Our approach takes advantage of a reference horizon, or paleogeotherm, established when high-T mineral thermochronometers across Marie Byrd Land (MBL) cooled from temperatures of \u003e800\u00b0 C to 300\u00b0 C, due to rapid regional extension at ~100 Ma . The event imparted a signature through which the subsequent Cenozoic landscape history can be explored: MBL\u0027s elevated geothermal gradient, sustained during the Cenozoic, created favorable conditions for sensitive apatite and zircon low-T thermochronometers to record bedrock cooling related to glacial incision. \r\n\r\nAnalyzing the chemistry of minerals (zircon and apatite) within fragments of eroded rock will reveal the rate and timing of the bedrock erosion and development of topography in West Antarctica. This collaborative project addresses the following questions: When did the land become high enough for a large ice sheet to form? What was the regional pre-glacial topography? Under what climate conditions, and at what point in the growth of an ice sheet, did glaciers begin to cut sharply into bedrock to form the narrow troughs that flow seaward? The research will lead to greater understanding of past Antarctic ice sheet fluctuations and identify precise timing of glacial incisionm which will clarify the onset of WAIS glacier incision and assess the evolution of Cenozoic paleo-topography. The collaborative project provides training for one graduate and 8 undergraduate students in STEM. These students, together with PIs, will refine West Antarctic ice sheet history and obtain results that pertain to the international societal response to contemporary ice sheet change and its global consequences. \r\n\r\nThe methods used for the research include: \r\n\u2022Low-temperature (T) thermochronology and Pecube 3-D thermo-kinematic modeling, applied to the timing and characterizatio episodes of glacial erosional incision. \r\n\u2022Single-grain double- and triple-dating of zircon and apatite, to determine the detailed crustal thermal evolution of the region, enabling the research team to identify the comparative topographic influences on glaciation versus bedrock uplift induced by Eocene to present tectonism/magmatism. \r\n\r\nStudents and PIs employed state-of-the-art analytical facilities in Arizona and Minnesota, expanding the geo- and thermochronologic history of MBL from bedrock samples and offshore sedimentary deposits. The temperature and time data we acquired will provide constraints on paleotopography, isostasy, and the thermal evolution of MBL that will be modeled in 3D using Pecube model simulations. Within hot crust, less incision is required to expose bedrock containing the distinct thermochronometric profile; a prediction we are testing through use of inverse Pecube 3-D models of the thermal field through which bedrock and detrital samples cooled. Using results from Pecube, the ICI-Hot team will examine time-varying topography formed in response to changes in erosion rates, topographic relief, geothermal gradient and/or flexural isostatic rigidity. These effects are manifestations of dynamic processes in the WAIS, including ice sheet loading, ice volume fluctuations, relative motion upon crustal faults, and magmatism-related elevation increase across the MBL dome. The project makes use of pre-existing sample collections housed at the US Polar Rock Repository, IODP\u0027s Gulf Coast Core Repository, and the OSU Marine and Geology Repository. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": -104.28, "geometry": "POINT(-132.22 -72.225)", "instruments": null, "is_usap_dc": true, "keywords": "Marie Byrd Land; GLACIERS/ICE SHEETS; Zircon; Subglacial Topography; FIELD SURVEYS; TECTONICS; Ice Sheet; Thermochronology; Apatite; ROCKS/MINERALS/CRYSTALS; Erosion; United States Of America; LABORATORY", "locations": "United States Of America; Marie Byrd Land", "north": -67.15, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": "PHANEROZOIC", "persons": "Siddoway, Christine; Thomson, Stuart; Teyssier, Christian", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "in progress", "repositories": "in progress", "science_programs": null, "south": -77.3, "title": "Collaborative Research: Ice sheet erosional interaction with hot geotherm in West Antarctica", "uid": "p0010386", "west": -160.16}, {"awards": "1443556 Thomson, Stuart; 1443342 Licht, Kathy", "bounds_geometry": null, "dataset_titles": "Apatite (U-Th)/He and TREE Data Central Transantarctic Mountains", "datasets": [{"dataset_uid": "601462", "doi": "10.15784/601462", "keywords": "Antarctica; Beardmore Glacier; Erosion; Landscape Evolution; Shackleton Glacier; Transantarctic Mountains; (U-Th)/He", "people": "Thomson, Stuart; Hemming, Sidney R.; Reiners, Peter; He, John; Licht, Kathy", "repository": "USAP-DC", "science_program": null, "title": "Apatite (U-Th)/He and TREE Data Central Transantarctic Mountains", "url": "https://www.usap-dc.org/view/dataset/601462"}], "date_created": "Wed, 09 Jun 2021 00:00:00 GMT", "description": "Antarctica is almost entirely covered by ice, in places over two miles thick. This ice hides a landscape that is less well known than the surface of Mars and represents one of Earth\u0027s last unexplored frontiers. Ice-penetrating radar images provide a remote glimpse of this landscape including ice-buried mountains larger than the European Alps and huge fjords twice as deep as the Grand Canyon. The goal of this project is to collect sediment samples derived from these landscapes to determine when and under what conditions these features formed. Specifically, the project seeks to understand the landscape in the context of the history and dynamics of the overlying ice sheet and past mountain-building episodes. This project accomplishes this goal by analyzing sand collected during previous sea-floor drilling expeditions off the coast of Antarctica. This sand was supplied from the continent interior by ancient rivers when it was ice-free over 34 million year ago, and later by glaciers. The project will also study bedrock samples from rare ice-free parts of the Transantarctic Mountains. The primary activity is to apply multiple advanced dating techniques to single mineral grains contained within this sand and rock. Different methods and minerals yield different dates that provide insight into how Antarctica?s landscape has eroded over the many tens of millions of years during which sand was deposited offshore. The dating techniques that are being developed and enhanced for this study have broad application in many branches of geoscience research and industry. The project makes cost-effective use of pre-existing sample collections housed at NSF facilities including the US Polar Rock Repository, the Gulf Coast Core Repository, and the Antarctic Marine Geology Research Facility. The project will contribute to the STEM training of two graduate and two undergraduate students, and includes collaboration among four US universities as well as international collaboration between the US and France. The project also supports outreach in the form of a two-week open workshop giving ten students the opportunity to visit the University of Arizona to conduct STEM-based analytical work and training on Antarctic-based projects. Results from both the project and workshop will be disseminated through presentations at professional meetings, peer-reviewed publications, and through public outreach and media.\r\n\r\n\r\nThe main objective of this project is to reconstruct a chronology of East Antarctic subglacial landscape evolution to understand the tectonic and climatic forcing behind landscape modification, and how it has influenced past ice sheet inception and dynamics. Our approach focuses on acquiring a record of the cooling and erosion history contained in East Antarctic-derived detrital mineral grains and clasts in offshore sediments deposited both before and after the onset of Antarctic glaciation. Samples will be taken from existing drill core and marine sediment core material from offshore Wilkes Land (100\u00b0E-160\u00b0E) and the Ross Sea. Multiple geo- and thermo-chronometers will be employed to reconstruct source region cooling history including U-Pb, fission-track, and (U-Th)/He dating of zircon and apatite, and 40Ar/39Ar dating of hornblende, mica, and feldspar. This offshore record will be augmented and tested by applying the same methods to onshore bedrock samples in the Transantarctic Mountains obtained from the US Polar Rock Repository and through fieldwork. The onshore work will additionally address the debated incision history of the large glacial troughs that cut the range, now occupied by glaciers draining the East Antarctic Ice Sheet. This includes collection of samples from several age-elevation transects, apatite 4He/3He thermochronometry, and Pecube thermo-kinematic modeling. Acquiring an extensive geo- and thermo-chronologic database will also provide valuable new information on the poorly known ice-hidden geology and tectonics of subglacial East Antarctica that has implications for improving supercontinent reconstructions and understanding continental break-up.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "LABORATORY; LANDSCAPE; AGE DETERMINATIONS; FIELD INVESTIGATION; GLACIAL PROCESSES; Transantarctic Mountains; USA/NSF; Thermochronology; Amd/Us; USAP-DC; TRACE ELEMENTS; Provenance Analysis; AMD; LANDFORMS; GLACIAL LANDFORMS", "locations": "Transantarctic Mountains", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Thomson, Stuart; Reiners, Peter; Licht, Kathy", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Collaborative Research: East Antarctic Glacial Landscape Evolution (EAGLE): A Study using Combined Thermochronology, Geochronology and Provenance Analysis", "uid": "p0010188", "west": null}, {"awards": "1543256 Shuster, David", "bounds_geometry": null, "dataset_titles": "Detrital low-temperature thermochronometry from Bourgeois Fjord, AP; Expedition Data; Expedition data of LMG1702", "datasets": [{"dataset_uid": "002733", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of LMG1702", "url": "https://www.rvdata.us/search/cruise/LMG1702"}, {"dataset_uid": "601259", "doi": "10.15784/601259", "keywords": "Antarctica; Antarctic Peninsula", "people": "Clinger, Anna", "repository": "USAP-DC", "science_program": null, "title": "Detrital low-temperature thermochronometry from Bourgeois Fjord, AP", "url": "https://www.usap-dc.org/view/dataset/601259"}, {"dataset_uid": "000402", "doi": "", "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition Data", "url": "https://www.rvdata.us/search/cruise/LMG1702"}], "date_created": "Fri, 29 Dec 2017 00:00:00 GMT", "description": "The extreme mountain topographies of alpine landscapes at mid latitudes (e.g., European Alps, Patagonia, Alaska) are thought to have formed by the erosive action of glaciers, yet our understanding of exactly when and how those topographies developed is limited. If glacial ice was responsible for forming them, then those landscapes must have developed primarily over the last 2-3 million years when ice was present at those latitudes; this timing has only recently been confirmed by observations. In contrast, the Antarctic Peninsula, which contains similarly spectacular topographic relief, is known to have hosted alpine glaciers as early as 37 million years ago, and is currently covered by ice. Thus, if caused by glacial erosion, the high relief of the peninsula should have formed much earlier than what has been observed at mid latitude sites, yet we know nearly nothing about the timing of its development. The primary benefit of this research will be to study the timing of topography development along the Antarctic Peninsula by applying state of the art chemical analyses to sediments collected offshore. This research is important because studying a high latitude site will enable comparison with sites at mid latitudes and test current hypotheses on the development of glacial landscapes in general.\u003cbr/\u003e\u003cbr/\u003eThis project aims to apply low-temperature thermochronometry based on the (U-Th)/He system in apatite to investigate the exhumation history, the development of the present topography, and the pattern of glacial erosion in the central Antarctic Peninsula. A number of recent studies have used this approach to study the dramatic, high-relief landscapes formed by Pleistocene alpine glacial erosion in temperate latitudes: New Zealand, the Alps, British Columbia, Alaska, and Patagonia. These studies have not only revealed when these landscapes formed, but have also provided new insights into the physical mechanisms of glacial erosion. The Antarctic Peninsula is broadly akin to temperate alpine landscapes in that the dominant landforms are massive glacial troughs. However, what we know about Antarctic glacial history suggests that the timing and history of glacial erosion was most likely very different from the temperate alpine setting: The Antarctic Peninsula has been glaciated since the Eocene, and Pleistocene climate cooling is hypothesized to have suppressed, rather than enhanced, glacial erosion. Our goal is to evaluate these hypotheses by developing a direct thermochronometric record of when and how the present glacial valley relief formed. We propose to learn about the timing and process of glacial valley formation through apatite (U-Th)/He and 4He/3He measurements on glacial sediment collected near the grounding lines of major glaciers draining the Peninsula. In effect, since we cannot sample bedrock directly that is currently covered by ice, we will rely on these glaciers to do it for us.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e CTD; IN SITU/LABORATORY INSTRUMENTS \u003e CHEMICAL METERS/ANALYZERS \u003e FLUOROMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e AWS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e ACOUSTIC SOUNDERS \u003e ECHO SOUNDERS; IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e THERMOSALINOGRAPHS", "is_usap_dc": false, "keywords": "R/V LMG; LMG1702; Antarctic Peninsula; ICE SHEETS", "locations": "Antarctic Peninsula", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Kohut, Josh; Shuster, David; Balco, Gregory; Jenkins, Bethany", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V LMG", "repo": "R2R", "repositories": "R2R; USAP-DC", "science_programs": null, "south": null, "title": "Antarctic Peninsula Exhumation and Landscape Development Investigated by Low-Temperature Detrital Thermochronometry", "uid": "p0000876", "west": null}, {"awards": "1246484 Balco, Gregory", "bounds_geometry": "POLYGON((-62 -63.5,-61.8 -63.5,-61.6 -63.5,-61.4 -63.5,-61.2 -63.5,-61 -63.5,-60.8 -63.5,-60.6 -63.5,-60.4 -63.5,-60.2 -63.5,-60 -63.5,-60 -63.6,-60 -63.7,-60 -63.8,-60 -63.9,-60 -64,-60 -64.1,-60 -64.2,-60 -64.3,-60 -64.4,-60 -64.5,-60.2 -64.5,-60.4 -64.5,-60.6 -64.5,-60.8 -64.5,-61 -64.5,-61.2 -64.5,-61.4 -64.5,-61.6 -64.5,-61.8 -64.5,-62 -64.5,-62 -64.4,-62 -64.3,-62 -64.2,-62 -64.1,-62 -64,-62 -63.9,-62 -63.8,-62 -63.7,-62 -63.6,-62 -63.5))", "dataset_titles": "Data repositories for UC-Berkeley/BGC thermochronometry and thermochronology research", "datasets": [{"dataset_uid": "001232", "doi": "", "keywords": null, "people": null, "repository": "PI website", "science_program": null, "title": "Data repositories for UC-Berkeley/BGC thermochronometry and thermochronology research", "url": "http://noblegas.berkeley.edu/~noblegas/datarepository.html"}], "date_created": "Mon, 02 Mar 2015 00:00:00 GMT", "description": "Intellectual Merit: \u003cbr/\u003eThe PIs propose to use the (U-Th)/He system in apatite to investigate the exhumation history, development of the present topography, and pattern of glacial erosion in the central Antarctic Peninsula. The Antarctic Peninsula has been glaciated since the Eocene and Pleistocene climate cooling is hypothesized to have suppressed, rather than enhanced, glacial erosion. To achieve these goals, the PIs will use a thermochronometric record of when and how the present glacial valley relief formed. A challenge to the proposed research is that, unlike Pleistocene glacial landscapes in temperate areas, the Peninsula is ice-covered and it is not possible to directly sample the bedrock surface. The PIs hope to learn about the timing and process of glacial valley formation through apatite (U-Th)/He and 4He/3He measurements on glacial sediment collected near the grounding lines of major glaciers draining the Peninsula. Learning how the Antarctic Peninsula landscape formed is important to discern how the mechanics of glacial erosion operate on long time scales, and to understand how glaciers mediate the interaction between climate change and orogenic mass balance. This work addresses a fundamental question in Antarctic earth science of how to infer geologic and geomorphic processes active on an ice-covered and inaccessible landscape.\u003cbr/\u003e\u003cbr/\u003eBroader impacts: \u003cbr/\u003eThis proposal will bring new researchers into the Antarctic research community. A proposed collaboration with British Antarctic Survey researchers will build an international collaboration. The outcomes of this project have ancillary importance to other fields and addresses fundamental challenges in Antarctic Earth Science.", "east": -60.0, "geometry": "POINT(-61 -64)", "instruments": null, "is_usap_dc": false, "keywords": "Antarctica; Not provided; ICE SHEETS; Antarctic Peninsula", "locations": "Antarctica; Antarctic Peninsula", "north": -63.5, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Shuster, David; Balco, Gregory", "platforms": "Not provided", "repo": "PI website", "repositories": "PI website", "science_programs": null, "south": -64.5, "title": "Antarctic Peninsula Exhumation and Landscape Development Investigated by Low-temperature Detrital Thermochronometry", "uid": "p0000067", "west": -62.0}, {"awards": "0739781 Blythe, Ann", "bounds_geometry": "POLYGON((155.77667 -79.793335,156.208836 -79.793335,156.641002 -79.793335,157.073168 -79.793335,157.505334 -79.793335,157.9375 -79.793335,158.369666 -79.793335,158.801832 -79.793335,159.233998 -79.793335,159.666164 -79.793335,160.09833 -79.793335,160.09833 -79.8578345,160.09833 -79.922334,160.09833 -79.9868335,160.09833 -80.051333,160.09833 -80.1158325,160.09833 -80.180332,160.09833 -80.2448315,160.09833 -80.309331,160.09833 -80.3738305,160.09833 -80.43833,159.666164 -80.43833,159.233998 -80.43833,158.801832 -80.43833,158.369666 -80.43833,157.9375 -80.43833,157.505334 -80.43833,157.073168 -80.43833,156.641002 -80.43833,156.208836 -80.43833,155.77667 -80.43833,155.77667 -80.3738305,155.77667 -80.309331,155.77667 -80.2448315,155.77667 -80.180332,155.77667 -80.1158325,155.77667 -80.051333,155.77667 -79.9868335,155.77667 -79.922334,155.77667 -79.8578345,155.77667 -79.793335))", "dataset_titles": "Thermochronologic and modelling test for a Mesozoic West Antarctic Plateau", "datasets": [{"dataset_uid": "600082", "doi": "10.15784/600082", "keywords": "Antarctica; Fission Track Thermochronology; Geochemistry; Solid Earth; Transantarctic Mountains", "people": "Huerta, Audrey D.; Blythe, Ann Elizabeth", "repository": "USAP-DC", "science_program": null, "title": "Thermochronologic and modelling test for a Mesozoic West Antarctic Plateau", "url": "https://www.usap-dc.org/view/dataset/600082"}], "date_created": "Fri, 07 Dec 2012 00:00:00 GMT", "description": "This project studies formation of the TransAntarctic Mountains (TAM) through numerical modeling based on cooling histories of apatite mineral grains. The TAM are the highest and longest rift-related mountain range in the world. Various models for their uplift have been proposed, the most provocative of which is that they are not uplifted, but instead are the eroded remnant of a plateau. This project evaluates that hypothesis by collecting apatites from around Byrd Glacier for fission track thermochronology. Results will be combined with a kinematic and thermal model to determine the TAM?s structural evolution. The plateau model, if correct, implies that the Byrd Glacier originated not as a glacier-carved valley through the TAM, but as a river system flowing in the opposite direction. Given that the Byrd Glacier is a key drainage for the East Antarctic ice sheet, this result has important implications for ice sheet models and interpretation of both regional geology and sediment records.\u003cbr/\u003e\u003cbr/\u003eThe main broader impacts are undergraduate research and a new collaboration between a primarily undergraduate and a research institution. Students will be involved in the field program, sample analyses, and numerical modeling.", "east": 160.09833, "geometry": "POINT(157.9375 -80.1158325)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -79.793335, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Blythe, Ann Elizabeth; Huerta, Audrey D.", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -80.43833, "title": "Collaborative Research: Thermochronologic and modelling test for a Mesozoic West Antarctic Plateau", "uid": "p0000677", "west": 155.77667}, {"awards": "0838722 Reiners, Peter; 0838729 Hemming, Sidney", "bounds_geometry": "POLYGON((-67.2 -58,-43.98 -58,-20.76 -58,2.46 -58,25.68 -58,48.9 -58,72.12 -58,95.34 -58,118.56 -58,141.78 -58,165 -58,165 -59.2,165 -60.4,165 -61.6,165 -62.8,165 -64,165 -65.2,165 -66.4,165 -67.6,165 -68.8,165 -70,141.78 -70,118.56 -70,95.34 -70,72.12 -70,48.9 -70,25.68 -70,2.46 -70,-20.76 -70,-43.98 -70,-67.2 -70,-67.2 -68.8,-67.2 -67.6,-67.2 -66.4,-67.2 -65.2,-67.2 -64,-67.2 -62.8,-67.2 -61.6,-67.2 -60.4,-67.2 -59.2,-67.2 -58))", "dataset_titles": "Erosion History and Sediment Provenance of East Antarctica from Multi-method Detrital Geo- and Thermochronology", "datasets": [{"dataset_uid": "600094", "doi": "10.15784/600094", "keywords": "Antarctica; Fission Track Thermochronology; Gamburtsev Mountains; Geochronology; Marine Sediments; Solid Earth; Southern Ocean", "people": "Hemming, Sidney R.", "repository": "USAP-DC", "science_program": null, "title": "Erosion History and Sediment Provenance of East Antarctica from Multi-method Detrital Geo- and Thermochronology", "url": "https://www.usap-dc.org/view/dataset/600094"}, {"dataset_uid": "600093", "doi": "10.15784/600093", "keywords": "Antarctica; Fission Track Thermochronology; Gamburtsev Mountains; Geochronology; Marine Sediments; NBP0101; ODP1166; ODP739; Prydz Bay; Solid Earth; Southern Ocean", "people": "Thomson, Stuart; Reiners, Peter; Gehrels, George", "repository": "USAP-DC", "science_program": null, "title": "Erosion History and Sediment Provenance of East Antarctica from Multi-method Detrital Geo- and Thermochronology", "url": "https://www.usap-dc.org/view/dataset/600093"}], "date_created": "Sun, 05 Jun 2011 00:00:00 GMT", "description": "This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Much of the inventory of East Antarctic bedrock geochronology, as well as a record of its erosional history, is preserved in Cenozoic sediments around its margin. This project is to use these sediments to understand their sub-ice provenance and the erosional history of the shield by measuring ages of multiple geo- and thermochronometers on single detrital crystals and on multiple crystals in detrital clasts (U/Pb, fission-track, and (U-Th)/He dating of zircon and apatite, and 40Ar/39Ar dating of hornblende, mica, and feldspar). The combination of multi-chronometer ages in single grains and clasts provides a powerful fingerprint of bedrock sources, allowing us to trace provenance in Eocene fluvial sandstones through Quaternary diamicts around the margin. Multiple thermochronometric (cooling) ages in the same grains and clasts also allows us to interpret the timing and rates of erosion from these bedrock sources. Delineating a distribution of bedrock age units, their sediment transport connections, and their erosional histories over the Cenozoic, will in turn allow us to test tectonic models bearing on: (1) the origin of the Gamburtsev Subglacial Mountains, (2) fluvial and topographic evolution, and (3) the history of glacial growth and erosion.", "east": 165.0, "geometry": "POINT(48.9 -64)", "instruments": null, "is_usap_dc": true, "keywords": "LABORATORY", "locations": null, "north": -58.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Reiners, Peter; Gehrels, George; Thompson, Stuart; Hemming, Sidney R.", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -70.0, "title": "Collaborative Research: Erosion History and Sediment Provenance of East Antarctica from Multi-method Detrital Geo- and Thermochronology", "uid": "p0000506", "west": -67.2}, {"awards": "0816934 Thomson, Stuart; 0817163 Reiners, Peter", "bounds_geometry": "POLYGON((72 -66,72.3 -66,72.6 -66,72.9 -66,73.2 -66,73.5 -66,73.8 -66,74.1 -66,74.4 -66,74.7 -66,75 -66,75 -66.3,75 -66.6,75 -66.9,75 -67.2,75 -67.5,75 -67.8,75 -68.1,75 -68.4,75 -68.7,75 -69,74.7 -69,74.4 -69,74.1 -69,73.8 -69,73.5 -69,73.2 -69,72.9 -69,72.6 -69,72.3 -69,72 -69,72 -68.7,72 -68.4,72 -68.1,72 -67.8,72 -67.5,72 -67.2,72 -66.9,72 -66.6,72 -66.3,72 -66))", "dataset_titles": "Triple-dating (Pb-FT-He) of Antarctic Detritus and the Origin of the Gamburtsev Mountains", "datasets": [{"dataset_uid": "600089", "doi": "10.15784/600089", "keywords": "Antarctica; Fission Track Thermochronology; Gamburtsev Mountains; Geochronology; Solid Earth", "people": "Thomson, Stuart", "repository": "USAP-DC", "science_program": null, "title": "Triple-dating (Pb-FT-He) of Antarctic Detritus and the Origin of the Gamburtsev Mountains", "url": "https://www.usap-dc.org/view/dataset/600089"}, {"dataset_uid": "600090", "doi": "10.15784/600090", "keywords": "Antarctica; Gamburtsev Mountains; Geochronology; Marine Sediments; NBP0101; ODP1166; Prydz Bay; Solid Earth; Southern Ocean", "people": "Reiners, Peter; Gehrels, George", "repository": "USAP-DC", "science_program": null, "title": "Triple-dating (Pb-FT-He) of Antarctic Detritus and the Origin of the Gamburtsev Mountains", "url": "https://www.usap-dc.org/view/dataset/600090"}], "date_created": "Thu, 30 Apr 2009 00:00:00 GMT", "description": "This Small Grant for Exploratory Research investigates the origin and evolution of the Gamburtsev subglacial mountains (GSM). These mountains are considered the nucleation point for Antarctica\u0027s largest ice sheets; however, being of indeterminate age, they may postdate ice sheet formation. As well, their formation could reflect tectonic events during the breakup of Gondwana. The project studies GSM-derived detrital zircon and apatite crystals from Prydz Bay obtained by the Ocean Drilling Program. Analytical work includes triple-dating thermochronometry by U/Pb, fission track, and (U/Th)/He methods. The combined technique offers insight into both high and low temperature processes, and is potentially sensitive to both the orogenic events and the subsequent cooling and exhumation due to erosion. In terms of broader impacts, this project supports research for a postdoctoral fellow and an", "east": 75.0, "geometry": "POINT(73.5 -67.5)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -66.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Thompson, Stuart; Reiners, Peter; Gehrels, George", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -69.0, "title": "Collaborative Research: SGER: Triple-dating (Pb-FT-He) of Antarctic Detritus and the Origin of the Gamburtsev Mountains", "uid": "p0000210", "west": 72.0}, {"awards": "9909436 Farley, Kenneth", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Wed, 11 Jul 2007 00:00:00 GMT", "description": "9909436 \u003cbr/\u003eFarley\u003cbr/\u003e\u003cbr/\u003eThis award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports an investigation of the uplift history of the Dry Valleys segment of the Transantarctic Mountains. The overall goal is to further constrain the exhumation history of the Transantarctic Mountains by using the newly developed apatite (U-Th)/He dating method on samples collected in vertical profiles. This approach, combined with existing apatite fission track information will constrain the rate and patterns of exhumation across the Transantarctic Mountains since their inception as a rift-flank uplift in the early Cenozoic.\u003cbr/\u003e\u003cbr/\u003eThis project will complement other projects and build on previous interpretations of the exhumation and tectonic history determined using apatite fission track thermochronology. It will bridge the gap between information on erosion rates determined from fission track thermochronology and from cosmogenic surface exposure dating and integrate the exhumation history of the mountains with their landscape evolution. As such, the results from this project will address an outstanding problem in Antarctic science; namely the stability of the East Antarctic Ice Sheet, and the timing of the transition from a \"warm\" dynamic ice sheet to a cold polar ice sheet. Highly relevant to this issue is the landscape evolution of the Transantarctic Mountains because many diverse lines of evidence for the rate of landscape evolution have been used to argue for a dynamic ice sheet up until either the Pliocene (the \"dynamic\" ice sheet model) or the middle Miocene (the \"stable\" ice sheet model). Understanding the past stability or dynamic fluctuations of the East Antarctic ice sheet with respect to the climate record is, of course, important for understanding how the present ice sheet may respond to global warming.\u003cbr/\u003e\u003cbr/\u003eThe specific objective of this project is to determine apatite (U-Th)/He age versus elevation trends for a number of vertical profiles from locations within the Transantarctic Mountain front and across the structural grain of the range. Fission track data already exist for all of these profiles, with apatite fission track ages ranging from 150-30 Ma. The greater precision of the (U-Th)/He technique and the fact it records information at lower temperatures (closure temperature of ~70 degrees Celsius; limits of 40-85 degrees Celsius for the He partial retention zone) will allow examination of the exhumation history of the TAM in more detail from ca 130 Ma to ~20 Ma. Another facet is to examine areas where Cretaceous exhumation is recorded and areas where the fission track profiles indicate periods of thermal and tectonic stability and minimal erosion throughout the Cretaceous. The variation of timing of the onset of more rapid exhumation accompanying uplift and formation of the Transantarctic Mountains in the early Cenozoic will also be examined.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": false, "keywords": "Not provided", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Farley, Kenneth", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": null, "title": "Collaborative Research: Exhumation of the Transantarctic Mountains: Constraints from (U-Th)/He Dating of Apatites", "uid": "p0000281", "west": null}]

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